Adjustable controller-finger.



PATENTED DEC. 5, 1905.

I. E. CASE.

ADJUSTABLE CONTROLLER FINGER.

APPLICATION FILED JULY 19, 1904.

lnvn I61. Frankfi Case by I 'UJHfi655625. X- m i624. Wu M UNITED STATESPATENT OFFICE.

FRANK E. CASE, OF SCHENECTADY, NEW YORK, ASSlUrN OR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

ADJUSTABLE CONTROLLER-FINGER.

Specification of Letters Patent.

Patented Dec. 5, 1905.

Application filed July 19, 1904. Serial No. 217,25

To all whom, it may concern.-

Be it known that I, FRANK E. CAsn, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in AdjustableController-Fingers, of which the following is aspecification.

My present invention relates to improvements in adjustablecontact-fingers for use in motor-controllers, reversing-switches, andsimilar electric-circuit-governing devices.

In controller-fingers commonly used it is necessary to make provisionfor adjusting them relatively to their cooperating contact members, forthe reason that on account of slight irregularities in the cast andmachined parts and the requirement of a support of some insulatingmaterial no two fingers would otherwise receive the same alinement. Itis evident that where the fingers are resilient or are spring-pressed,as they must necessarily be in order to secure a close and efficientcontact, any change in the alinement of a finger produces a variation inthe pressure, with which the finger bears against its cooperatingmember, a deflection from the normal in one direction producing tooheavy a pressure, and consequently too much friction and wear betweenthe parts, and a deflection in the opposite direction resulting, if inany contact at all, in too light a pressure between the parts and a badcontact. Adjustability is also desirable to compensate for the wearwhich takes place during service in order that the predeterminedpressure between contacts may be maintained.

It has been proposed to provide a resilient finger with means to varyits inclination with respect to its support; but the arrangementsheretofore devised have produced a change in the effective tension ofthe finger, because, assuming the finger to be adjusted so as to have anormal tension, a further adjustment in one direction increases thetension and an adjustment in the opposite direction decreases'it.

The object of the present invention is to so construct contact-fingersthat they may be adjusted to compensate for any irregularities which mayexist in parts thereof, for defects in mounting, and for wear withoutaltering vide means which may be operated easily and quickly and whichshall positively retain the parts in their adjusted positions.

In the accompanying drawings, which illustrate my invention in one ofits forms, Fig-' ure 1 is a side elevation of my improved contact-fingerin operative engagement with a cooperative contact-surface, and Fig. 2is a cross-section taken on line 2 2 of Fig. 1.

The contact-finger as a whole is indicated by A, and B represents acomplementary contact-surface, which may be a segment of a rotatablecylinder or which may have any other desired form.

The finger comprises a suitable base 1, by which it is secured in itsposition as part of an operative control equipment, the resilient memberor stem 2, carrying at its free end the contact-tip 3, the rigid memberor backing 4, secured at one end to the resilient stem 2 at a point nearthe base, and the adjusting means. The resilient member 2 is shown asconsisting of the stitf spring-piece 5 and a piece 6, which latter maywith advantage be made up of a series of thin copper strips. Thecontact-tip 3 may be secured to the pieces 5 and 6 in any desired wayas,for instance, by riveting.

The adjusting means for the finger is illustrated in the form of aset-screw 7, passing freely through a fixed part which may comprise astiff plate or arm 8, secured to the base 1 by means of screws or rivetswhich hold the stem 2 in place and screw-threaded into the backing i. Itis apparent that when the set-screw is operated the only etfect upon thestem 2 is to move it through an angle about the point a as a center inthe same manner that it, if rigid and pivoted at a, would be swung aboutits pivot, the effective portionthat beyond the point I), the point atwhich the members 2 and L are secured togetherremaining entirelyundisturbed. Consequcntl y whenever the contact-tip is adjusted so as tobe deflected through a predetermined distance upon making contact thepressure between the two contact-surfaces will be the same irrespectiveof the angle which the finger makes with its support.

The set-screw 7, as illustrated, consists of a threaded shank 9, thehead 10, the collar 11, and a neck 12 between the head and the collar.The neck of the set-screw is seated in an open-ended slot in the arm 8,while the head and collar hold the screw against axial movement. Thecollar 11 is provided with one or more flat faces 13, which are adaptedto be engaged by the lips 14 of the springcatch 15 in order to hold theset-screw against rotation. The locking-spring 15 is convenientlypositioned by having one end thereof secured in place in common with theparts 2 and 8. In order to adjust the finger, the locking-spring 15 ismoved out of engagement with its collar 11, whereupon the set-screw maybe turned to give the contact-tip its desired position. Upon releasingthe spring 15 it again engages the flat face or faces of the collar andholds the screw against rotation and the parts in their adjustedpositions.

The member 4 when constructed somewhat along the lines illustratedpossesses functions more important than that of a mere nut for thereception of the end of the set-screw. By making it of a considerablelength and forming it with an offset portion 16 for securing it to theresilient member of the finger at a point near the base the efiectivelength of the resilient member need not be very materially decreased,and at the same time the hole for receiving the set-screw may be sostationed that no difficulty is experienced in turning the screw. Thefree end of the member serves as a stop which engages the resilientmember and limits its rearward movement, thereby protecting it frominjury. The contact-tip, as shown, is provided with a lug 17, which isarranged to engage with the member A to limit the forward movement ofthe tip and resilient member. This construction also enables theresilient member to be placed under an initial tension when in itsextreme forward position, thereby affording a distinct and materialpressure between the contactsurfaces before the contact-tip has begun tomove backwardly.

From the above description of my invention it is evident that adjustmentis provided for changing the position of the contact-surface of thefinger without affecting the pressure with which the finger will bearupon a cooperating contact member under conditions otherwise equal,thereby giving the greatest efficiency. It is further evident theadjustment may be rapidly and effectively made and in a manner whichobviates the use of locking or jam nuts.

Although it is apparent that peculiar advantages result from certain ofthe details of construction illustrated, yet the present invention inits broader aspects is not limited to such details.

hat I claim as new, and desire to secure by Letters Patent of the UnitedStates, is

1. A contact-linger embodying a resilient contact member, a support, andmeans for changing the inclination of the resilient member with respectto its support without altering the effective tension of the resilientmember.

2. A contact-linger embodying a resilient member fixed at one end to asupport, and means for changing the inclination of the resilient memberwith respect to its support without altering the effective tension ofthe resilient member.

3. A contact-linger embodying a resilient member and its support, arigid member, and adjusting means between the rigid member and thesupport, said rigid and resilient members being secured together at apoint intermediate the support and the adjusting means.

4. A contact-finger embodying a resilient member, a rigid member mountedthereon, a support for the resilient member, and adjusting means betweensaid support and the rigid member.

5. A contact-linger embodying a resilient member, a rigid member securedto the resilient member at one point and normally out of engagementtherewith throughout the remainder of its length, a support, andadjusting means between the support and said rigid member.

6. A contact-finger embodying a resilient member, a rigid member securedat one end to the resilient member and normally out of contact therewiththroughout the remainder of its length, means for adjustably fixing therigid member, and a stop on one of said members for limiting therelative movements thereof.

7. A contact-finger embodying a resilient member and its support, arigid member mounted upon the back of the resilient member andadjustably connected with said support, and a stop on one of saidmembers for limiting the forward movement of the resilient member withrespect to the rigid member.

8. A contact-finger embodying a resilient member and its support, arigid member secured to said resilient member near its fixed end andextending toward the free end of the resilient member but out of contacttherewith, a lug upon the resilient member for engaging the rigid memberto limit the relative movements of the two members, and an adjustableconnection between the rigid member and the support.

9. A contact-finger embodying a resilient member and its support, meansfor placing said member under an initial tension, and means for changingthe inclination of the resilient member with respect to its support saidcontact member and the support, fixed collars for preventing axialmovement of the screw, and a catch for normally preventing rotarymovement thereof.

In witness whereof I hereunto set my hand this 18th day of July, 1904.

FRANK E. CASE.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

